Indicating fuse plug



Nov. 29, 1938. H. M. MUNCHERYAN 2,138,769

INDICATING FUSE PLUG Filed Jan. 27, 1937 2 Sheets-Sheet l InsuurnonINVENTOR HPand M. Mun ch EPHHTI BY ATTORNEY.

Nov. 29, 1938.

H. M. MUNCHERYAN 2,138,769

lNDICATTNG FUSE PLUG Filed Jan. 27, 1957 2 Sheets-Sheet 2 9 I INVENTOR.69 67 7/ Hrand M. Muncheryan PMQJM A TTORNEY.

Patented Nov. 29, 1938 UNITE STATES PATENTv OFFiCE INDIGATING FUSE PLUGHrand M. Muncheryan, Los Angeles, Calif.

Application January 27, 1937, Serial No. 122,588

15 Claims. (Cl. 200-130) My invention relates to a fuse plug of thegenof insulation that are utilized for supporting the oral typedisclosed in United States Letters Patnd cat g fus in position Withinthe P .ent No. 2,067,977 issued to me January 19, 1937, Fig. 8 is avertical section similar to Fig. 2 and the principal objects of myinvention are and showin a modified term of he se and also 5 togenerally improve upon and simplify the cona modified arrangement ofSupporting the fuse 5 struction of the plug disclosed in my aforesaidWithin the p patent, as well as other forms of similar fuse Fig. 9 is aperspective View with parts broken plugs, and to provide improved meansfor indiaway and showing a part of the fuse supporting eating thecondition of the fuse, that is, whether means that is utilized in theform of plug illus- 10 or not the fuse has been blown or ruptured as atrated in Fig. 8. 10 result of overload of current in the circuit inFig, 10 is a plan view of a modified form of which the fuse plug islocated. the fuse supporting means.

A further object of my invention is to provide 11 is a oss Se t on ta enOn the line an improved form of device that carries means, of g. eitherintegrally or separately formed, for indig- 12 s a V w looking againsthe u ders de 15 eating the condition of the fuse, and spaced por- 0f theform of fuse mounting illustrated in Figs.

tions of said fuse adjacent and beyond the con- 10 and 11 With Partsbroken y d in S edition indicating means being restricted or madetiOIlnarrow or thin, to form definite points that fuse 13 is a P p e V Oa o st uct o and rupture when the fuse is subjected to an that y beutilized Supporting a portion o 20 overload of current, v the fusecondition indicating means within the A further object of my inventionis to provide D Chamber- 7 means for supporting the fuse in position be-14 is a p p V w Of a urther modified neath the window or transparentarea in the top form of y improved indicating e P of the plug and toarrange the electrical connec- Fig. 15 is a vertical cross section takenon the 25 tions between the contacts of the plug and the line f fuse sothat the current carri d by the fuse and 16 s a p pe e V ew Of one formof the connections is caused to positively pass through indicating fuseused in the p the thin or narrow portions of the fuse, thus ig. 17 is ape p V Of a modified form bringing about the rupture or blowing of thefuse 0f the indicating fuSeat the restricted points so as to release andde- 13 is a p ew Of a modified form of stray th t portion t t carries tcondition p the fuse and the condition indicating characters eatingcharacters. By removing or destroying arried thereby that portion of thefuse that carries the fuse con- 5115- 19 a cross Section taken on theline dition indicating characters, an observer, by notlgflg of 35 ingthe absence of such characters beneath the 15 perspectlve VleW showmgthe nection between a current carrying member and an insulated disk, andwhich construction is used in certain forms of the indicating fuse plug.

Fig. 21 is a plan view of a further modification of the indicating fuseplug.

Fig. 22 is a plan View of the form of plug illustrated in Fig. 21, andshowing the fuse blown or ruptured at two points so as to expose theunderwindow of the plug, will readily understand that the plug is unfitfor further service.

With the foregoing and other objects in view my invention consists incertain novel features of construction and arrangement of parts thatwill be hereinafter more fully described and claimed and illustrated inthe accompanying drawings, in

whlch: lying member of the plug indicating means 45 Fig 1 1s a top planof a fuse plug Fig. 23 is a cross section taken on the line 23 structedin accordance with my invention, 23 of Fig Fig, 2 is a cross sectiontaken on the line 2--2 Fjg 24 5 2 27 and 23 are plan views f of Fig. 1.modified forms of fuses that are adaptable for Fig, 3 is a top plan viewof the fuse plug with use in my improved indicating fuse plug. 50 partsbroken away and in section and showing Referring by numerals to theaccompanying the fuse blown or ruptured at two spaced points drawings,and particularly to the construction so as to entirely release the fusecondition indiillustrated in Figs. 1 to 7, inclusive, 10 designateseating characters. a fuse body of conventional form and composed Figs.4:, 5, 6 and '7 are perspective views of disks of insulating materialsuch as glass, porcelain or 55 composition, said body having a chamber II, and mounted on the exterior of the intermediate portion of the bodyis a shell I2 of metal in which is pressed a thread in order that theplug may be screwed into the conventional socket.

Located in the lower end of the body of the plug and extending into thelower portion of chamber II is a contact I3 that is adapted to engagethe center contact of the socket in which the plug is positioned.

The upper portion of the chamber I I is slightly enlarged with respectto the lower portion, thus forming an internal shoulder I4 in the upperportion of said chamber, and positioned on top of the plug and providinga cover for the chamber II, is a disk I5 of transparent material,preferably mica, that is held in position by a metal rim I6 thatencircles the upper end of body ID. The section of mica I5 provides awindow whereby the fuse that is positioned in the enlarged upper portionof the chamber II may be readily observed.

Resting on shoulder I 4 is the edge of a thin disk II of insulation andformed at diametrically opposite points in the edge thereof are notchesI8 and positioned above and spaced apart from said disk I? is a seconddisk I9 of insulation pro vided in its edge with diametrically oppositenotches 20 that are adapted to register with the notches i8, and formedat or near the center of disk I9 is an aperture 2| (see Figs. 4 and 5).

In some instances the disks I! and I3 may be provided at diametricallyopposite points with slots or apertures 22 that coincide with each otherwhen positioned in the plug above the shoulder I4, and said slots orapertures performing the functions of the notches I8 and 20 (see Figs, 6and 7).

Positioned on top of disk I! is a thin strip of metal 23 that functionsas a conductor, and the outer end of said conductor extends through anaperture 24 in the wall of the plug and this end of the strip iselectrically connected to the shell I2.

The inner end of conductor 23 extends upwardly through an aperture 2| inthe upper disk I9 and the end of said strip above said disk is bentdownwardly so as to lie flat on the upper surface of said disk I9.

One end of a strip of metal 25 that functions as a conductor and a fuseis electrically connected to the center contact I3 and said stripextends upwardly to a point beneath the center of disk II and thenextends at right angles outwardly against the underside of said disk,thence upwardly through the coinciding notches I8 and 20 on one side ofthe disks I! and I9, thence diametrically across the upper disk I9,thence downwardly through the opposite pair of notches 20 and I8, thencebeneath the disk I! and the end of this portion of the strip is providedwith ears 26 that are bent around and beneath the edges of that portionof the strip that lies beneath the disk I1, and which extends at rightangles from the substantial upright portion that is connected to contactI3.

The general form of this combined conductor strip and fuse isillustrated in Fig. 17.

As illustrated in Fig. 1, the intermediate portion of that section ofthe conductor and fuse that extends across disk I9 and which is indirect contact with the end of conductor 23 that lies flat on the centerof disk I9, is formed with fuse indicating characters, for instance, theletters OK, the same being cut from the metal forming the fuse andconductor, and the sides of these characters are connected to the mainbody of the fuse and conductor by relatively narrow portions 21, andwhich latter are ruptured or blown in the event of an excess or overloadof current through the plug.

In Fig. 17 I have shown the intermediate portion of that section of thefuse and conductor that overlies the disk I9, in the form of a plate 28,and fuse indicating characters, for instance, the letters OK or the wordGood may be marked or stamped on the upper surface of said plate.

To retain the disks II and I9 in proper position within the fuse plugwith the edge of the lower disk I1 resting on the shoulder I4, a spacingring or collar 29 of insulating material is positioned between the edgeof disk I9 and the under face of the transparent disk I5.

The construction just described provides for the rupturing or blowing ofthe fuse at two points to the sides of the indicating characters thatform a part of the fuse and thus when the fuse ruptures or blows as aresult of overload of current, the indicating characters or that portionbetween the narrow connections 21 will be freed and distorted and dropso that an observer may readily note that the fuse has blown andtherefore is unfit for further service.

Where this form of fuse is blown or ruptured as a result of overload ofcurrent, said current passes from contact I3 through that portion of theconductor 25 that is connected to said contact, thence through one endof a loop of which the indicating characters form a part, therebyrupturing one of the narrow portions 2'! and immediately current passesthrough the other end of the loop and blows or ruptures the other one ofthe narrow connecting members 21, thus freeing and distorting thecharacters or that portion of the fuse between the narrow connections21.

In the modified construction illustrated in Figs. 8 and 9, theconstruction of the body of the plug is practically the same as thatheretofore described and illustrated in Figs. 1 to 3 inclusive, andresting on the shoulder I4 within the plug is a single disk 30 ofsuitable insulating material provided in its edge at diametricallyopposite points with notches 3 I, and formed in the center of this diskof insulation is an aperture 32.

Connected to the center contact I3 located in the bottom of the plugbody is one end of a strip of metal 33 that functions as a conductor,and the upper end of this strip is provided with a horizontal C-shapedplate 34 that rests against the under face of disk 30 around the opening32 therein.

Projecting inwardly from the ends of the C-shaped plate 34 and thenceupwardly through the aperture 32 and thence outwardly on top of disk 30,are contact ears 35.

Overlying the disk 38 is a combined conductor and fuse indicating strip35 formed of metal, the end portions thereof extending through apertures31 formed in the wall of the plug, and said ends being electricallyconnected to the threaded shell I2 on the surface of the plug.

The intermediate portion of the conductor 36 is in direct contact withthe ears 35 and this portion of the fuse is formed with indicatingcharacters, for instance, the letters OK or said intermediate portionmay be in the form of a plate bearing the letters OK or the word Good.

In this form of plug portions of the strip 39 to the sides of the fuseindicating characters or the plate that bears such characters, arereduced in width or thickness as designated by 38, so as to define thepoints at which the fuse blows or is ruptured in the event of anoverload of current.

In the modified construction illustrated in Figs. 10 to 12 inclusive, adisk 39 of insulation overlies a lower disk 46, and formed atdiametrically opposite points on the edge of disk 39 are notches 4|, andextending inwardly from thecenters of said notches are narrower notches42.

Formed at diametrically opposite points in the edge of the lower disk 46are notches 43 that coincide with the notches 4| in the upper disk andpassing through the notches 4| and 43 are the end portions of a strip ofmetal 44 that functions as a conductor and a fuse condition indicatingmember.

The intermediate portion of the upper member of the loop 44, or thatportion that extends across the top of disk 39, is cut to form fusecondition indicating characters, for instance, the letters OK, and aportion 45 of the strip extends from the bottom of the loop 44 beneaththe lower disk 49 downwardly, and this portion is electrically connectedto the center contact in the bottom of the plug body.

Extending diametrically between the disks 39 and 40 is a conductor strip46 of metaL'the ends of which are bent upwardly through the narrownotches 42 in the upper disk 39 and the ends of this strip are extendedover the upper face of said upper disk 39 to provide contacts thatengage the overlying portion of the loop 44.

This conductor strip 46 is electrically connected to the threaded shellon the exterior of the plug by a narrow strip of metal 41.

Formed in the side edges of the overlying portion of conductor strip 44beyon the fuse condition of conductor strip 44 beyond the fuse condisamebeing located just beyond the ends of the conductors 46 that lie on topof disk 39, thus forming relatively narrow portions 49 in the fusestrip, and which portions are ruptured or blown in the event of overloadof current through the plug.

In the modified construction illustrated in Figs. 14 and 15, the plugbody 50 having a chamber 51, is provided at its upper end with a window52, at its lower end, with a center contact 53, and on the surface ofthe intermediate portion of the plug is a threaded shell 54.

Formed through the upper portion of the wall of the plug is a passageway55 that is occupied by the vertical leg of an inverted L-shaped metalconductor 56, the lower end thereof being electrically connected toshell 54. The horizontal leg of this conductor 56 extends horizontallyinto the upper portion of the chamber within the plug between two disksor sections 57 of insulating material. The inner end of the horizontalleg of the conductor 56 extends upwardly through the upper one of thedisks of insulation and this end is bent'downwardly to lie flat on theupper surface of said upperdisk.

One end of a strip of metal 58 that functions as a conductor and fusecondition indicating character, is connected to contact 53 and extendsupwardly and the upper portion of said strip is formed into a loop 59that encircles the disks 5'! of insulation, with the upper portion ofsaid loop in direct contact with the end of the conductor 56 that lieson top of the upper disk.

That portion of strip 58 that overlies the upper end of the disks 51functions as a fuse and, as illustrated in Fig. 16, this, portion may beformed with fuse indicating characters such as OK, or

this particular portion may be in the form of a plate having marked onitsupper surface fuse indicating characters.

Portions of the conductor 58 to the sides of the fuse conditionindicating characters, are made narrow, as designated by 66, in order toprovide spaced points beyond said characters where the fuse blows orruptures in the event of an overload of current.

In Fig. 13 I have illustrated a construction. wherein a pair ofconductors 6i extend upwardly in the. chamber within the plug, the lowerends of which conductors are connected to the center contact 53. Theupper ends of said conductors are bent to form horizontally disposedhooks 52 that receive and hold an inserted card or piece of insulation63 bearing on its upper face characters to indicate that the fuse hasblown, for instance, the word Bad. Where this construction is used it isnot necessary to use in the upper portion of the chamber of the plugdisks of insulation such as I1, 23 and 39.

A fuse such as 36 or 58 carrying fuse indicating characters such as OKor Good overlies and extends lengthwise of the member with portions ofthe body of the fuse beyond the condition designating characters makingdirect contact with the upper portions of the ears 62.

ms, when the fuse blows or is ruptured as a result of overload ofcurrent, the condition indicating characters forming a part of orcarried by the fuse, will drop away from their normal positions so as toexpose the section of insulation 63 that is marked with charactersshowing that the plug is unfit for further service.

In the modified construction illustrated in Figs. 18 and 19, theintermediate portions of a conductor fuse 64 formed of thin metal, hasportions 65 folded over the ends of a card or section of insulation 66bearing on its upper surface fuse condition indicating characters suchas OK. That portion of the fuse between the bent portions 65 extendsbeneath the card 66 and portions of the conductor fuse just beyond thebent portions 95 are made narrow to provide points where the fuseruptures in the event of an overload of current, thus freeing the fusecondition indicating card or member 66.

In the modification illustrated in Figs. 21 to 23 inclusive, the loopportion 610, of a conductor fuse practically identical with the form ofconductor fuse illustrated in Fig. 17, passes around an upper disk 6'5and a lower disk 53, both of insulating material. This loop is connectedto one of the contacts of the plug and the intermediate portion of theupper member of the loop is in the form of a plate 69 on the uppersurface of which appear fuse indicating characters, for instance, theword Good, or the letters OK.

This plate 69 is connected to the body of the conductor fuse by narrowportions if! which rupture in the event of an overload of currentthrough the fuse.

Appearing on the upper face of the upper disk 61 and concealed as longas the plate 69 is in its normal position, are fuse indicatingcharacters, for instance, letters forming the word Bad, and whichletters are exposed when the fuse is ruptured and the overlying plate 69drops away from its normal position.

Interposed between the disks 6'! and 99 is a conductor II that isconnected to one of the con tacts of the plug, and the ends of saidconductor extend upwardly through notches or apertures in tor makedirect contact with the conductor 66 at points just beyond the narrowportions 70 of the upper member of the loop.

In Figs. 24 and 25 I have illustrated modified forms of the fuse whereinthat portion that is disposed between the narrow points where the fuseis ruptured in the event of an overload of current bears on its upperface data relating to the capacity of the fuse in amperes.

In Fig. 26 I have illustrated the conductor fuse having a portion cut toform condition indicating characters 72, for instance, the outline ofthe letters OK and when the material forming the fuse is bent over astrip of insulation along the lines a:x, these letters appear on top ofthe strip without displaying the adjacent portions of the fuse.

Portions of the letters 12 are made narrow to form definite points wherethe fuse ruptures in the event of an overload of current, and suchrupturing obviously destroys the fuse condition indicating characters soas to show that the plug in which the fuse is located is unfit forfurther service.

In Fig. 27 I have illustrated a form of fuse wherein the fuse conditionindicating character bearing plate 13 is disposed at right angles to themain body of the fuse.

In Fig. 28 I have illustrated condition indicating characters such asthe letters OK integral with and on the sides of the main body of theconductor fuse.

Thus it will be seen that I have provided an indicating fuse plug thatis relatively simple in construction, inexpensive of manufacture andvery effective in performing the functions for which it is intended.

In all cases the construction of the plug and conductor fuse is suchthat in the event of an overload of current through the plug the fuse iscaused to rupture or blow out at two or more spaced points, therebyreleasing and practically destroying a substantial portion of the fuse,and which portion bears fuse condition indicating characters, and thusafter a fuse has blown an inspection of the plug will readily andpositively indicate that the plug has been ruptured and therefore thatit is unfit for further service.

It will be understood that minor changes in the size, form andconstruction of the various parts of my improved indicating fuse plugmay be made and substituted. for those herein shown and describedwithout departing from the spirit of the invention, the scope of whichis set forth in the appended claims.

I claim as my invention:

1. The combination with a fuse plug having a chamber and a window, of aconductor fuse arranged within the chamber in the plug and having aportion positioned adjacent the window in said plug, said portionbearing fuse condition indicating characters, and means for causing saidconductor fuse to rupture at a plurality of points so as to release anddestroy that portion of the fuse bearing the fuse condition indicatingcharacters.

2. A conductor fuse having a portion constituting a closed loop and aconductor portion leading from said closed loop, a portion of said loophearing fuse condition indicating characters and said loop havingrestricted portions positioned adjacent the ends of that portion bearingthe fuse condition indicating characters.

3. The combination of a fuse plug having a chamber, a window andelectrical contacts, of a fuse arranged within the chamber in said plug,a portion of said fuse being positioned adjacent the window in the plugand bearing fuse condition indicating characters, said fuse having aplurality of restricted fusible portions located beyond that portionthat bears the fuse condition indicating characters, an electricalconnection in relation with the fuse-condition indicating characters andone of said conductor contacts positioned in close relation with saidcharacters but in remote relation with said restricted fusible portionsto determine the points where the fuse ruptures in the event of anoverload of current therethrough, and electrical connections between thecontacts of the plug and said fuse to cause the fuse to rupture at therestricted points in the event of an overload of current through saidfuse.

4. The combination of a fuse plug having a chamber, a window andelectrical contacts, of a fuse arranged within the chamber in said plug,a portion of said fuse being positioned adjacent the window in the plugand bearing fuse condition indicating characters, said fuse having aplurality of restricted portions located beyond that portion that bearsthe fuse condition indicating characters to determine the points wherethe fuse ruptures in the event of an overload of current therethrough,electrical connections between the contacts of the plug and said fuse tocause the current to rupture at the restricted points in the event of anoverload of current through said fuse, and a second indicating means,positioned beneath that portion of the fuse that bears thefuse-condition indicating means, being disclosed thereof after the firstfuse-condition indicating means is released and destroyed as a result ofan overload of current, and thereby indicating that the fuse is unfitfor further service.

5. In a fuse plug, having a chamber, a window, and a fusible elementhaving a portion adjacent said window, a plurality of fusible narrowportions extending from the said portion adjacent the window, saidportion adjacent the window constituting fuse condition indicating meansand means including a contact and a conductor for supporting saidfusible element adjacent said window.

6. In a fuse plug having a chamber, a window, and a pair of electricalcontact terminals, a fuse element disposed in said chamber in the plugand bearing fuse-condition indicating means, a plurality of insulatingplates located beneath the said window, a portion of said fuse elementextending through said insulating plates and exposed to a portion of theelectrical contact terminal causing an electrical connection between thesaid contact terminals of the fuse and said condition indicating meansand insulating the rest of that portion of the fuse element whichoccupies the said plug chamber from the said contact terminals.

7. In a fuse plug, having a chamber, a window, and electrical conductorsconsisting of a shell and an upright center contact, a fuse elementhaving a portion adjacent said window, said portion having fusecondition indicating means and having its ends electrically connected tothe said shell restricted, fusible portions on each side of said fusecondition indicating means, and means whereby said fuse-conditionindicating portion of the fuse makes electrical connection with saidcenter contact and is supported thereon in an indicative position.

8. A conductor fuse having portions forming current-carryingfuse-condition indicating characters and portions of said charactersbeing restricted to form definite points of rupture as a result ofoverload of current, said conductor fuse having extensions at each endof the said indicating characters and adapted to support said indicatingcharacters and to retain the indicating characters in spaced relation inorder to cause flow of current only through the reduced portions of thesaid characters.

9. The combination with a fuse plug having a chamber and a window, of aconductor fuse arranged within the chamber in the plug and having aportion positioned adjacent said window, said portion bearingfuse-condition indicating characters, and current conducting meansconnected to the ends of said spaced fuse-condition indicatingcharacters so as to divide the course of the current through the saidindicating characters into a plurality of current carrying pathscorresponding to the number of restricted portions of the fuse conditionindicating characters.

10. In a fuse plug, having a chamber, a window and a pair of spacedcontacts electrically connected together by means of a fusible conductorin the said chamber, said fusible conductor having integralcurrent-carrying fuse-condition indicating characters adjacent saidwindow, and ourrent-limiting narrow fusible portions located at theextremities of the said indicating characters and forming a portion ofthe path of the current through the said fuse-condition indicatingcharacters.

11. In a fuse plug, a conductor fuse having means for indicating thenormal condition of operation of the said fuse and having, a pluralityof restricted portions positioned adjacent said fuse-conditionindicating means and adapted to rupture in the event of an overload ofcurrent through the fuse, and electrical conductors connected to saidfuse condition indicating means and dividing the current between saidrestricted portions.

12. In a fuse plug, a conductor fuse having means for indicating thecondition of said fuse,

and a plurality of restricted fusible portions connected to said fusecondition indicating means for dividing the course of the current intosame number of current paths as there are restricted portions, andpermitting said fuse condition indi cating means to be released anddestroyed upon an overload of current through the said fuse and itsrestricted portions.

13. In a fuse plug having a chamber, a window, and spaced terminalelectrical contacts, a fusible conductor connecting said spacedcontacts, said fusible conductor bearing means for indicating the normaloperative condition of the fuse and located adjacent said window, saidindicating means having spaced reduced portions adapted to rupture as aresult of an overload of current and portions adapted to make electricalconnection with one of the said terminal contacts and supported inupright operative position thereupon.

14. A conductor fuse having portions forming current-carryingfuse-condition indicating means cut from said conductor to formcurrent-conducting characters and portions of said characters beingrestricted in cross sectional area to define points of rupture when saidfuse is subjected to an overload of current, said defined points ofrupture constituting portions of said characters forming the path of thecurrent through the fuse.

15. In an article of manufacture, a fusible element a portion of whichconstitutes fuse-condition indicating characters, fusible restrictedpor-- tions located in proximity of said indicating means, extensionsfrom each of said restricted portions and forming diiferent currentpaths thereof, a number of said extensions making electrical connectionwith portions of the fuse circuit having like electrical polarity, andthe rest of said extensions making electrical connection with portionsof the circuit having a polarity opposite to that of the first.

HRAND M. MUNCHERYAN.

